Niederfinow boat lift - Wasser- und Schiffahrtsamt Eberswalde

the caisson in the case

the caisson in the case of larger disturbances in equilibrium. It consists of an irreversible screw spindle (rotary crosspiece), which is moved in a full-length slotted nut (central spindle column). These central spindle columns are connected to the lift framework while the rotary crosspieces are fitted to the caisson. The drive units are accommodated in engine rooms on the superstructure of the caisson. They are connected with each other by a shafting loop line (ø 130 mm) to guarantee complete synchronisation. Each of the four drives consists of a spring-mounted pinion driven via four spur-geared back gears by an electric motor. A direct-current motor is the drive unit for each machine. The motor operates on the first countershaft via a flexible membrane clutch. The electrical installations on the caisson are primarily for the operation of the caisson. The four drive motors are direct-current shunt motors of a power of 55 kW (75 horsepower). The speed of the four motors is regulated automatically by the control unit using the Ward-Leonard speed-control system in a range of 60 to 700 revolutions per minute, during one trip from start to stop. The technical specifications of the Ward-Leonard converter are: 16 Drive motor: 310 kW; 380 V three-phase current; 25% duty cycle; 140 rpm Control generator: 277 kW; 479 V DC; 25% duty cycle; 1,450 rpm Excitation generator: 15 kW; 230 V DC; 25% duty cycle; 14,50 rpm The major overhaul in the years 1984- 85 included the larger part of the mechanical engineering and electrotechnical systems. During this period, all 256 cables were replaced, all cable sheave supports were replaced, and the electrical systems of the upper and lower pounds as well as the caisson were renewed. After a short interruption further repairs took place in the following areas: ■ reconditioning of the sealing frame drives of the upper and lower pounds, ■ renewal of the ring shaft, ■ construction of the winch traction facility with original reproduction of the towing towers. Repair measures will be completed within the next few years with the reconditioning of the rotary crosspieces. Through the regeneration of the elements of the system, it is possible to maintain the tried and tested technology at a level which prolongs the working life of the boatlift and allows continued, uninterrupted operation. Rack ladder Central spindle column Pinion Upper and lower pillar units Rotary crosspiece Seal Schematic cross-section of the boatlift Drive Cable sheaves Cable sheave girders Cables Walkway Counterweights Lateral braces Main caisson girder Cable compensation chain Caisson cross girder Largest elevation: 37,21 m Caisson length: 85,00 m Caisson widt: 12,00 m 17